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* The MIT License
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* 
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//
// Novell.Directory.Ldap.Rfc2251.RfcMessageID.cs
//
// Author:
//   Sunil Kumar (Sunilk@novell.com)
//
// (C) 2003 Novell, Inc (http://www.novell.com)
//

using Novell.Directory.Ldap.Asn1;

namespace Novell.Directory.Ldap.Rfc2251
{
    /// <summary>
    ///     Represents an Ldap Message ID.
    ///     <pre>
    ///         MessageID ::= INTEGER (0 .. maxInt)
    ///         maxInt INTEGER ::= 2147483647 -- (2^^31 - 1) --
    ///         Note: The creation of a MessageID should be hidden within the creation of
    ///         an RfcLdapMessage. The MessageID needs to be in sequence, and has an
    ///         upper and lower limit. There is never a case when a user should be
    ///         able to specify the MessageID for an RfcLdapMessage. The MessageID()
    ///         class should be package protected. (So the MessageID value isn't
    ///         arbitrarily run up.)
    ///     </pre>
    /// </summary>
    internal class RfcMessageID : Asn1Integer
    {
        /// <summary>
        ///     Increments the message number atomically
        /// </summary>
        /// <returns>
        ///     the new message number
        /// </returns>
        private static int MessageID
        {
            get
            {
                lock (lock_Renamed)
                {
                    return messageID < int.MaxValue ? ++messageID : (messageID = 1);
                }
            }
        }

        private static int messageID;
        private static readonly object lock_Renamed;

        /// <summary>
        ///     Creates a MessageID with an auto incremented Asn1Integer value.
        ///     Bounds: (0 .. 2,147,483,647) (2^^31 - 1 or Integer.MAX_VALUE)
        ///     MessageID zero is never used in this implementation.  Always
        ///     start the messages with one.
        /// </summary>
        protected internal RfcMessageID() : base(MessageID)
        {
        }

        /// <summary> Creates a MessageID with a specified int value.</summary>
        protected internal RfcMessageID(int i) : base(i)
        {
        }

        static RfcMessageID()
        {
            lock_Renamed = new object();
        }
    }
}